Metallic thermometer.



C. E. MERRYMAN. METALLIC THBHMOMETER. APPLICATION FILED'QOT. 27, 1910.

Patented Mar. 12,1912.

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UNITED STATES PATENT OFFICE.

CLARENCE n. MERRYMAN, or ANDERSON, INDIA A.

METALLIC THERMOMETER.

To all whom it may concern:

Be it known that I, CLARENCE E. MERRY- MAN, a citizen of the United States, residentof Anderson, in the county of Madison and State of Indiana, have made a certain new and useful Invent-ion in Metallic Thermometers; and I declare the following to be a full, clear, and exact description of the same, such as will enable others skilled in the art to which it appertains to make and use the invention, reference being had to the accompanying drawings, and to letters or figures of reference marked thereon, which form a partof this specification,

The invention relates to metallic thermometers designed for use with alarm devices or signals, the invention being designed primarily for use with alarms for incubators but being capable of use with fire alarms, in schools or hospitals or in the rooms of invalidsforgiving notice when the air temperature needs correction.

The invention consists in the novel construction and combinations of parts as hereinafter set forth.

In the accompanying drawings, illustrating the invention, Figure 1 is a central vertical longitudinal section of my invention; Fig. 2 is a front View of the same; Fig. 3 is a section -on the line 3-3, Fig. 1; and F igQ 4 is a detail perspective view of a modification wherein the-indicator has an oifset end engaging a slot of the loose'end disk.

In these drawings the numeral 1 designates an incasement or supporting frame composed of an end bar 2, upper and lower parallel longitudinal bars 3 and 4 connected with said end bar and a partially circular end piece 5 also connected with the bars 3 and 4 to form a rigid frame, and provided with a forward arcuate or partially circular extension 5*.

Located centrally between the upper and lower bars 3 and 4 is a longitudinal rod 6 having at its rear end a disk 7 fixed thereto, said disk being alsogfixedly secured toa set screw 8 engaging a threaded perforation in the end bar'2. A coiled spring 9 surrounds the central or axial rod 6, said spring being fixed at its rear end to the disk 7,-

an intermediate disk 10 and an end disk 11 being both rotatably or loosely mounted upon the rod 6 and serving in connection with thedisk 7 to support the spring, the forward end of which is secured to the end Specification of Letters Patent.

Application filed October 27, 1910.

Patented Mar. 12, 1912.

Serial No. 589,479.

and about on a line with the forward edge of said extension from said extension. In this way a chamber 141 is formed between the frame end piece 5, which forms the back of said chamber, and the dial plate, which forms the front of said. chamber.

The coiled spring is composed of an inner coiled portion of one metal, such as steel, and an outer coiled portion of another metal, such as brass, riveted or soldered together and having different coefficients of expansion or contraction, this spring" being so disposed as to be out of contact with the longitudinal frame bars so that it may rotate or turn as the air temperature becomes greater or less, a radial indicator or hand 16 being revolubly mounted upon the forward end of the rod 6 and secured to the disk 11 to turn therewith, said indicator being located in the chamber between the dial plate and back.

17 is a stud upon the dial plate, upon which are revolubly mounted radial. alarm indicators or hands 18 and 19, insulated from the dial plate at 18*, said hands having inturned free ends, 18 and 19 respectively, extending throughthe arcuate slot 15 and with which the free end of the indicator 16 is adapted to make contact respectively when the air temperature is too low or too high.

Upon the stud 17 is screwed a nut 20 forming with said stud a binding post for a wire connection 21 to an electric battery 22. Below and adjacent to this binding post is a second binding post 23, -located upon the dial plate at the lower central portion thereof and adapted for connection of ofi'set end 16 in engagement with an eccentric slotor perforation 11 of the disk 11 and turning therewith, as shown in Fig. 4 of the drawings.

A cylindrical tube 26 of tin or other suitable metal is slipped over the bars 2 and 3 and surrounds the spring, serving to protect the same. The frame 1 has supports 1* for the attachment of the device to the side wall of an incubator or other inclosure. The invent-ion is of simple and durable nature, easily made and applied, andwhen placed close to a stove or furnace Will give notice when the fire is toohot for safety or too low for comfort or that it needs attention. The indicators are preferably tipped with platinum to insure-a good electrical contact.

Having thus described my invention, what I claim'as new and desire to secure by Letters Patent is:

A metallic thermometer, comprising an incasement having at one enda graduated dial plate and an arcuateyslot-and at its op--' posite end a set-screw, a fixed disk upon said set-screw, a rod in said incasernent in line with said set-screw and havlng at one end fixed connection therewith and at its oppo intermediate loose disk upon said rod,- a

thermostatic coil composed of inner and outer metal coils of different coefiicients of expansion surrounding said rod and having at one end fixed connection with said fixed disk and at its opposite end fixed connection with said loose disk, said coil resting upon said interm'ediate'disk, and a radial indicator having at one end a fixed connection with said loose disk to turn therewith and at it opposite end extending in register with said slot.

In testimony whereof I aflix my signature, in presence of two witnesses. CLARENCE E. MERRYMAN.

Witnesses:

JAMES F. FRY, CHARLES E. HALE; 

